1. Field of the Invention
The present invention relates to a train for laying a new railroad track, which comprises at least means for transporting and laying the cross-ties, rail positioning means and tie storage cars.
2. Description of the Prior Art
It is already known from the Swiss Patent No. CH-A-600,045 to construct a railroad renewal train comprising two hingedly interconnected trucks supporting the various working tools for removing the old track and laying the new track, together with one or more cars for storing the new and old cross-ties. The storage cars and the first truck, usually referred to as the tie handling car, travel on the old track while the second truck rolls on the renewed track. During the works, the tie handling car is carried at its front end by a bogie and at the rear end by a pair of retractable bearings rolling on an auxiliary runway consisting of the new rails to be laid on the track but deposited beforehand on both sides of the old track and externally of the ties. The second or power truck is supported at its front end by the tie handling car and at its rear end by a bogie rolling on the renewed track.
Another Swiss Patent No. CH-A-600,046 discloses a track renewal train similar to the one described in the above-mentioned Swiss Patent No. CH-A-600,045 but adapted, at the cost of a few transformations, to be used as a railroad track laying train (cf. FIGS. 5 and 6). The track laying train operates in the direction opposed to that of the track renewing train. The retractable rolling bearings are disposed on either side of the single bogie of the power truck, whereby this power truck travels on the rails disposed directly on the platform of the future track and set at the proper gage by the rolling bearings. The tie laying device is located just behind the power truck bogie and ahead of the rail positioning device so that the two bogies of the second truck roll on the freshly laid track.
French Patent Appln. No. FR-A-2,419,998 filed by the same Applicant describes a railroad track removal train which is also adapted to be converted into a train for laying a new track. Like the above-mentioned trains, the train described in French Patent Appln. No. FR-A-2,419,998 is composed of two hingedly interconnected working trucks supporting the various working tools and machines. The essential difference existing between this train and the previous ones is that the single bogie of the power truck is already rolling on the new track while the bogie of the tie handling truck, which travels in the working area, is mounted on a translation system adapted to slide or roll in the rail seats cut in the old railless cross-ties. The second bogie of the same car rolls on the old track together with the various storage cars. To convert this last-mentioned train into a train for laying a new track, the direction of travel is reversed and the single bogie of the second hinged truck is provided with tires enabling it to travel on the track platform while the second translation device supporting one of the bogies of the second truck travels on the laid track and the second bogie and the storage cars roll on the laid track.
The previously mentioned railroad track laying trains are objectionable in that the power vehicle or in any case the first working truck must travel while bearing either on rails laid directly upon the platform or, in the absence thereof, directly on the platform proper. In either case the load supported by the platform is localized at the positions of the rolling bearings so that the pressure exerted on the platform without the ties is extremely high. This load localization is attended by the destruction of the platform profile. In fact, it is particularly important, prior to laying the ties and rails, to level and profile the platform as a function of the geometrical configuration of the track and also of the specific nature of the soil (slope in curved sections, platform inclination for draining rainwater, etc.). Therefore, after the passage of the power vehicle or after the track-laying operation, the platform must be reprofiled, thus increasing costs and extending the track construction time. In case the profile were not restored, a local settling or even a total destruction of the track might result. Furthermore, constituting a runway by laying rails directly on the platform is an inconvenience per se.